There are a wide variety of wet end additives used for strengthening paper products. For instance, water-soluble polyacrylamides have been used to impart dry strength and temporary wet strength to paper products. Such polymers must have sufficient cationic character to provide an affinity to paper fibers and can be made thermosetting to improve their strength-enhancing character.
One known class of polyacrylamide strengthening agents includes materials which have been modified with glyoxal to make them thermosetting. Due to poor stability, however, the molecular weights of current glyoxalated polyacrylamides continue to increase, even at room temperature, until the polymers gel. Thus, the art continues to search for ways for producing glyoxalated polyacrylamide strengthening agents of improved stability.